Chart hub



Oct 4, 1949 G. E. NICHOLSON ET AL 2,483,427

CHART HUB Filed March- 21, 1946 IN VEN TOR 7 'im-MM Patented Oct. 4, 1949 CHART HUB George E,

Nicholson and John B. McGay, Tulsa,

Okla, vassignors to .OhmerCoz-poration,Dayton, Ohio, a corporation ofNewXork Application. March 2.1, 19416, Ser'nali No. 655,916

4'Claims. 1 This inventionrelates-to charthubs and. more particularly, but not-by way of limitation, to ya chart hub adapted tobe usedon recordingim struments and the like. ,This application is a continuation-impart .of applicants .co epreceding application No. \5.63,301, filed November 13, .1944, now abandoned, fora chart hub.

In present day recording .meters utilizing a circular chart vthat has to be periodically replaced, the hub for holding the chart to the meter=is usually threaded on to a meter shaft and must be taken off in order to replace the chart. This hasmany disadvantages in that it requires unscrewing of the hub during replace ment of .the chart, which is unhandy for the operator, whomay. drop. the hub. and. lose. it. ,Furthermore, during the replacementof the chartit is often necessarytohold-thc chart while threading the hub back on tothe meter shaft which usually causes .disalignment of the chart especially in setting .thechart .for .aspecifiedtime, To overcome these disadvantages many present day recording meters utilize various .means for preventing removal of thechart-hub from the meter. As an example, a chain or lever attached tothehub positioned in front. .ofthe-cha-rt .tor securing the. hub to the meter case,

.Itis. an important object of the present inven tion to provide .a chart. hub tor a recording. meter that willallow replacement of the circular chart for the meter without removing the chart hub from the .metershaft.

.A further. object. of the invention is to provide a non-removable .chart huballowing-replacement of a chart of .a recording instrument expeditiously andyet efiectively-securing the chart to the meter.

Another object of the invention is to provide a non-removable chart hub for a recording meter which is efficient and easy to operate, durable and easy to manufacture.

And an additional object of this invention is to provide a non-removable chartihub for a recording meter wherein the clamping members move into clamping position toward thehub in such manner to preventtearing of the chart.

"with these and other objects "in view, there hasben illustrated on the accompanying drawing one form in which the invention may be conveniently embodied in practice.

In the drawings:

Fig. 1 is aside elevational view partly in section of the chart hub-in open position.

Fig. 2 is a similar .view showing the hub in semi-closed or semi-clamping position,

:1 ill Fig. 3 15a similar View showing the hub in final clam-ping position.

Fig. 4 a is an I elevational view of the hub shown attached to a recording meter or the like.

Fig. 5-is an'end elevation of thecha rtjhub.

- Referring now to the drawings-in detail, reference character 2 represents the hub assembly comprising a tubular stud 12 having a tapered central bore d'adapted to fit on ma shaft-6 of the-recording meterli utilizing a replaceable circular chart It. The tubular stud l2-has-an annular flange portion 14 formedwi-th'or-secured to one end thereof. The-opposite end of the stud 12 is of a reduced diameter'to provide a threaded portionlG fora purpose'as willbe hereinafter set forth. A plurality of circumferenti-ally spaced longitudinal slotsor g-roovesll are provided in the-stud-member l2 and extend'at one end beyondthe chart 'contactingfacels' of the flange 14 asat I-8, and at their other ends into the threaded portion [5. These end portions of the grooves are substantially parallel with the stud axis-and their base walls are connected'by the longitudinally concave cam surfaces -20. 'In each'of the grooves -11 is provided a clamping member-22 having reversely bent leg portions 24 and 26 at opposite ends thereof. The leg- 24 has a terminal projection 28 adapted to ride along-thecam surface 20. The'bend forming leg "24 provides an abutment or clamping face 30 disposed at an acute angle to theshank portion of the clampingimember :22 forapurpose as will'be hereinafter set forth. Each leg 26 has'rockable bearing contact on the stud and is loosely engaged in aninternal annular recess 32 0f a nut-34 threadedon'tothe "threads it of the stud l2. Theouter periphery of the nut'is preferably knurled to facilitate operation thereof. It '-will*bc understood thatthree-grooves'll and complementary clamps Hare preferable as shown but theinvention is not limit d thereto.

"Theouteryperiphery ofthe stud 12 between the ends of grooves Ills-provided 'withan annular groove which is disposed "an annular wire or retaining spring 38 for holding the clamps 21in posit-ion in'the'grooves ll. 'Itwill be apparent that the legs 26 of the clamps cooperate with the recess-32=and-the outer end walls of grooves 1''! -to prevent complete unthreading and removal of the nut 34 from the threaded portion IS of the stud l2. The large diameter portion of stud l2 and the nut 34 are of substantially equal diameter, which is predetermined with relation to the opening in the chart l0, so that when clamping members 22 are in the retracted position of Figure 1, the chart may be readily applied over said nut and stud and guided by the latter to contact the face l4 of flange M in accurately concentric relation with the meter shaft 6, as shown in Figure 4.

Operation The chart is securely clamped in its applied position by threading th nut 34 inwardly on the stud. Clamping members 22 are thus moved toward the chart and as the terminals 28 thereof ride over the cam surfaces 20 they move radially outward in the respective slots H until the clamping faces 30 are disposed at right angles to the stud axis and parallel with the plane of the chart in opposed relation to the face of the latter. At this time and before contact of the faces 30 with the chart H], the terminals 28 enter the respective slot portions l8, as seen in Figure 2. Thus in the further adjustment of nut 34 the clamping members are held against further radial displacement relative to the stud and chart to prevent thrust pressure against the edge of the opening in the chart or eccentric displacement of the chart relative to the axis of the stud. While maintaining this parallel relationship between the face of the chart and the clamping faces 30, in the final adjustment of the nut 34 and clamping elements 22, the chart will be securely clamped between said faces 30 and the face of the flange I4 by uniform pressure contact of the clamping members with the chart. As the terminals 28 of the clamping elements are confined in the slot portions I8, angular displacement of the clamping members relative to the stud from this position, and accidental release of the clamping pressure is impossible. This feature also obviates possible tearing or mutilation of the chart.

When a record has been completed the chart may be easily and quickly removed by threading the nut 34 outwardly on the stud 12 to withdraw the members 22 from clamping positions. In the continued outward movement of the nut the terminals 28 of the clamping members leave the slot portions I8 and ride inwardly toward the stud axis until the opposite ends of said members abut the outer end walls of slots l1, thereby preventing further unthreading of the nut and its disconnection from the stud. The clamping members are retained in this position by the ring 38, as seen in Figure 1, with the end portions 24 thereof wholly within the slots I! so that the chart may be readily removed without tearing or mutilation, over the large diameter section of the stud l2 and the nut 34. A new chart is then applied and securely clamped against the flange I4 in the manner above explained.

It will be apparent that in the present structure the bore 4 is slightly tapered in order to provide a tight fit of the hub on a preferably tapered shaft 6 of the meter 8; however, any other similar means, such as threads and the like, may be provided for securing the hub 2 on to the meter shaft.

In the foregoing it will be apparent that the present invention effectively secures a chart to a recording meter and furthermore allows replacement of the chart on the meter without removing the clamping portion of the chart hub from the meter, thereby overcoming many disadvantages prevalent in present day chart hubs.

Changes may be made in the details of the invention disclosed herein without departing from the spirit of the invention, as expressed in the following claims.

What we claim is:

1. Chart holding means for recording instruments, comprising a stud adapted to be fixed to a movable part of the instrument, said stud having a chart supporting surface at one end, a member axially adjustable on the other end of said stud, a plurality of clamping elements operatively connected at one of their ends to said member for axial and radial movement relative to the stud in the adjustment of said member, each of said elements adjacent to its other end having an angularly disposed chart clamping face and a terminal portion projecting therefrom, means on the stud coacting with said terminal portions in the axial adjustment of said elements toward the chart to radially move said elements relative to the stud and position the clamping faces thereof in opposed substantially parallel relation to the chart, and additional means on said stud coacting with the terminal portions of said elements to restrain said elements against further radial displacement in the continued axial movement thereof to final chart clamping position.

2. Chart holding means for recording instruments as defined in claim 1, wherein said clamping elements are disposed in longitudinal grooves formed in said stud and said means for radially moving said elements comprises a cam surface on the base wall of each groove.

3. Chart holding means for recording instruments as defined in claim 2, together with a retaining element circumscribing the stud between the ends of said grooves and coacting with the clamping elements in the retracted position thereof to retain the same wholly within said grooves.

4. Chart holding means for recording instruments as defined in claim 1 wherein said adjustable member is threaded on the stud and provided with an internal groove in which the first named ends of said clamping elements are rockably engaged, together with additional means on the stud and said members coacting with said first named ends of the clamping elements to limit retracting movement of said member and prevent disconnection thereof from said stud.

GEORGE E. NICHOLSON. JOHN B. McGAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

